Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON):

Solution:
#!/bin/python
n0,m0=map(int,raw_input().split())
transposed=False

if n0>m0:
    transposed=True
    n,m=m0,n0
else:
    n,m=n0,m0

grid=[[0 for j in range(m)] for i in range(n)]

#print n0,m0,n,m,grid
for i in range(n0):
    line=map(int,raw_input().split())
    for j in range(m0):
        if transposed:
            grid[j][i]=line[j]
        else:
            grid[i][j]=line[j]
#print grid

#instructions
rowInsts=[0 for i in range(n)]
colInsts=[0 for i in range(m)]

for i in range(n):
    lo=min(grid[i])
    rowInsts[i]=lo
    grid[i]=[e-lo for e in grid[i]]

for j in range(m):
    col=[r[j] for r in grid]
    #print col
    lo=min(col)
    hi=max(col)
    if lo!=hi:
        print -1
        raise SystemExit
    colInsts[j]=lo

print sum(rowInsts)+sum(colInsts)
if transposed:
    for i in range(n):
        for j in range(rowInsts[i]):
            print 'col',i+1
    for i in range(m):
        for j in range(colInsts[i]):
            print 'row',i+1
else:
    for i in range(n):
        for j in range(rowInsts[i]):
            print 'row',i+1
    for i in range(m):
        for j in range(colInsts[i]):
            print 'col',i+1

#print grid